Eighteen subjects responded to sentences which differed in context (whether a preceding sentence referred to their subject or object), intonation (3 alternatives) and voice (active or passive). Differences in response times indicate that context and voice make a significant difference to the ease of processing sentences, both as main effects and in interaction with each other and with intonation. Conclusions are drawn regarding the control of these variables in psychological experiments and the empirical validity of Halliday's linguistic theory.
